Résumé
Background: In the era of climate change, urban areas like Paris face heightened public health challenges, especially during heatwave occurrences. Although there is growing awareness, a research void exists regarding the intersectional effects of heatwaves, environmental variables, and demographic factors in dense urban locales such as Paris.Methods: Using a retrospective methodology, we collected comprehensive data from the National Health Data System and the Technical Agency for Information on Hospitalization. This encompassed 471,814 hospital stays from June to September, spanning from 2009 to 2019. Hospitalizations were systematically categorized into ten distinct clusters, each representing a specific set of medical conditions or reasons for hospitalization. These clusters include: (I) electrolyte disorders including dehydration and hyponatremia, (II) renal insufficiency, (III) urinary tract infections and lithiasis, (IV) septicemia, sepsis, and bacteremia, (V) heatstroke, (VI) neurocardiovascular diseases, (VII) chronic heart failure, (VIII) chronic respiratory diseases, (IX) diabetes mellitus, and (X) addictions and mental health issues. Each cluster is defined based on specific criteria, including diagnostic codes and clinical characteristics, allowing for a more precise analysis of hospitalization trends in relation to environmental factors such as heatwaves. Days identified as heatwaves were determined using a percentile-based approach. The study examined the correlations between hospitalization rates and various determinants using mixed-effects log-linear regression models.Results: Our study utilized a comprehensive dataset covering 2,184,193 residents across 20 districts in Paris. The data reflected a range of differences in demographics, building characteristics, and reasons for hospitalization. Notably, the age group over 75 was identified as a significant factor influencing hospitalization rates. This was further analyzed in conjunction with environmental metrics, including peak temperatures and the FDEP15 index.Conclusions: The intricate web of demographics, environmental stimuli, and heatwave events profoundly shapes public health trajectories in Paris. As the climate crisis deepens, there’s an urgent call for customized healthcare interventions, especially targeting the vulnerable elderly demographic.